1. Field of the Invention
The present invention relates to a control valve and, more particularly, to a mixed water control valve for a faucet to control the temperature of a mixture of cold and hot water of the faucet.
2. Description of the Related Art
A conventional faucet comprises a control valve to mix the cold water from a cold water source and the hot water from a hot water source and to inject the mixed water outwardly for use with a user. Thus, the mixed water has a proper temperature so that the user can use the water comfortably. However, when the water flow from the cold water source or the hot water source is reduced or stops accidentally due to an irregular condition, the water pressure of the cold and hot water is not balanced, so that the water temperature is increased or decreasing to an excessive extent instantaneously to make the water too hot or too cold, thereby easily causing an uncomfortable sensation to the user due to the too cold water or evenly causing danger to the user due to the too hot water (the user is easily scalded by the too hot water).
A conventional control valve for a faucet comprises a valve housing, a control unit mounted on the valve housing, and a balance unit mounted in the valve housing. The valve housing has a bottom provided with a mounting seat which has two water inlet holes. One of the two water inlet holes of the mounting seat is connected to a cold water source, and the other one of the two water inlet holes of the mounting seat is connected to a hot water source. The balance unit includes a fixed sleeve secured the mounting seat, and a pressure regulating sleeve movably mounted in the fixed sleeve. In operation, the cold water from the cold water source and the hot water from the hot water source in turn flow through the two water inlet holes of the mounting seat and the fixed sleeve into the pressure regulating sleeve respectively. In such a manner, when the water flow of a first one (for example, the cold water terminal) of the water inlet holes is reduced accidentally or stopped abnormally due to an irregular condition, the water pressure of the first one (the cold water terminal) of the water inlet holes is reduced or disappears. Thus, the greater water pressure of a second one (for example, the hot water terminal) of the water inlet holes will push the pressure regulating sleeve so that the pressure regulating sleeve is moved in the fixed sleeve so as to reduce or stop the water flow of the second one (the hot water terminal) of the water inlet holes. Thus, the pressure regulating sleeve is moved by a pressure differential between the two water inlet holes so that the water flow of the two water inlet holes can be regulated by movement of the pressure regulating sleeve so as to achieve a water pressure balance and to stabilize the temperature of the mixed water in the valve housing. However, when the (cold or hot) water only flows through one of the two water inlet holes of the mounting seat, while other water equipment is also opened simultaneously, a larger pressure is applied on the pressure regulating sleeve to push and move the pressure regulating sleeve violently, thereby easily producing a resonant noise in the faucet. In addition, the pressure regulating sleeve is moved quickly in the fixed sleeve due to the larger pressure so that the pressure regulating sleeve will hit or wear the fixed sleeve, thereby decreasing the lifetime of the balance unit.